Currently, the medical valve inside that is applied widely is typically composed of a housing, a valve core, a lock ring and a spring, wherein the housing is a hollow structure, the valve core is made of a material with quite small rigidity and elasticity and is installed within the housing to be in clearance fit with the housing, and the lock ring and the spring are sleeved outside the valve core and also inside the housing. When in use, a gas injection device is in airtight connection with a gas inlet of the valve inside and pushes the valve core inwards, as a result, the spring is compressed to drive the lock ring to move away from the gas inlet, thus gas can flow in through a clearance between the lock ring and the housing; upon the completion of gas injection, the gas injection device is pulled out and the spring then pushes the valve core to move outwards, as a result, the lock ring returns to the original position to block off the clearance between the valve core and the housing again to achieve the sealing effect.
Such medical valve insides have the defects as follows: 1, interference is liable to occur during magnetic resonance imaging examination owing to the presence of a metal component, i.e. the spring; and 2, the assembly is complex owing to plenty of components, therefore, the production cost is relatively high.